/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.notepad;

import android.app.Activity;
import android.content.ComponentName;
import android.content.ContentValues;
import android.content.Context;
import android.content.Intent;
import android.content.res.Resources;
import android.database.Cursor;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.net.Uri;
import android.os.Bundle;
import android.provider.BaseColumns;
import android.util.AttributeSet;
import android.util.Log;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.EditText;
import android.widget.Toast;

import com.example.android.notepad.NotePad.NoteColumns;

/**
 * A generic activity for editing a note in a database. This can be used either to simply view a note
 * {@link Intent#ACTION_VIEW}, view and edit a note {@link Intent#ACTION_EDIT}, or create a new note
 * {@link Intent#ACTION_INSERT}.
 */
public class NoteEditor extends Activity {
	private static final String TAG = "NoteEditor";

	/**
	 * Standard projection for the interesting columns of a normal note.
	 */
	private static final String[] PROJECTION = new String[] {
			BaseColumns._ID, // 0
			NoteColumns.NOTE, // 1
			NoteColumns.TITLE, // 2
	};
	/** The index of the note column */
	private static final int COLUMN_INDEX_NOTE = 1;
	/** The index of the title column */
	private static final int COLUMN_INDEX_TITLE = 2;

	// This is our state data that is stored when freezing.
	private static final String ORIGINAL_CONTENT = "origContent";

	// The different distinct states the activity can be run in.
	private static final int STATE_EDIT = 0;
	private static final int STATE_INSERT = 1;

	private int mState;
	private Uri mUri;
	private Cursor mCursor;
	private EditText mText;
	private String mOriginalContent;

	/**
	 * A custom EditText that draws lines between each line of text that is displayed.
	 */
	public static class LinedEditText extends EditText {
		private Rect mRect;
		private Paint mPaint;

		// we need this constructor for LayoutInflater
		public LinedEditText(Context context, AttributeSet attrs) {
			super(context, attrs);

			mRect = new Rect();
			mPaint = new Paint();
			mPaint.setStyle(Paint.Style.STROKE);
			mPaint.setColor(0x800000FF);
		}

		@Override
		protected void onDraw(Canvas canvas) {
			int count = getLineCount();
			Rect r = mRect;
			Paint paint = mPaint;

			for (int i = 0; i < count; i++) {
				int baseline = getLineBounds(i, r);

				canvas.drawLine(r.left, baseline + 1, r.right, baseline + 1, paint);
			}

			super.onDraw(canvas);
		}
	}

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);

		final Intent intent = getIntent();

		// Do some setup based on the action being performed.
		final String action = intent.getAction();
		if (Intent.ACTION_EDIT.equals(action)) {
			// Requested to edit: set that state, and the data being edited.
			mState = STATE_EDIT;
			mUri = intent.getData();
		} else if (Intent.ACTION_INSERT.equals(action)) {
			// Requested to insert: set that state, and create a new entry
			// in the container.
			mState = STATE_INSERT;
			mUri = getContentResolver().insert(intent.getData(), null);

			// If we were unable to create a new note, then just finish
			// this activity. A RESULT_CANCELED will be sent back to the
			// original activity if they requested a result.
			if (mUri == null) {
				Log.e(TAG, "Failed to insert new note into " + getIntent().getData());
				finish();
				return;
			}

			// The new entry was created, so assume all will end well and
			// set the result to be returned.
			setResult(RESULT_OK, (new Intent()).setAction(mUri.toString()));

		} else {
			// Whoops, unknown action! Bail.
			Log.e(TAG, "Unknown action, exiting");
			finish();
			return;
		}

		// Set the layout for this activity. You can find it in res/layout/note_editor.xml
		setContentView(R.layout.note_editor);

		// The text view for our note, identified by its ID in the XML file.
		mText = (EditText) findViewById(R.id.note);

		// Get the note!
		mCursor = managedQuery(mUri, PROJECTION, null, null, null);

		// If an instance of this activity had previously stopped, we can
		// get the original text it started with.
		if (savedInstanceState != null)
			mOriginalContent = savedInstanceState.getString(ORIGINAL_CONTENT);
	}

	@Override
	protected void onResume() {
		super.onResume();
		// If we didn't have any trouble retrieving the data, it is now
		// time to get at the stuff.
		if (mCursor != null) {
			// Requery in case something changed while paused (such as the title)
			mCursor.requery();
			// Make sure we are at the one and only row in the cursor.
			mCursor.moveToFirst();

			// Modify our overall title depending on the mode we are running in.
			if (mState == STATE_EDIT) {
				// Set the title of the Activity to include the note title
				String title = mCursor.getString(COLUMN_INDEX_TITLE);
				Resources res = getResources();
				String text = String.format(res.getString(R.string.title_edit), title);
				setTitle(text);
			} else if (mState == STATE_INSERT)
				setTitle(getText(R.string.title_create));

			// This is a little tricky: we may be resumed after previously being
			// paused/stopped. We want to put the new text in the text view,
			// but leave the user where they were (retain the cursor position
			// etc). This version of setText does that for us.
			String note = mCursor.getString(COLUMN_INDEX_NOTE);
			mText.setTextKeepState(note);

			// If we hadn't previously retrieved the original text, do so
			// now. This allows the user to revert their changes.
			if (mOriginalContent == null)
				mOriginalContent = note;

		} else {
			setTitle(getText(R.string.error_title));
			mText.setText(getText(R.string.error_message));
		}
	}

	@Override
	protected void onSaveInstanceState(Bundle outState) {
		// Save away the original text, so we still have it if the activity
		// needs to be killed while paused.
		outState.putString(ORIGINAL_CONTENT, mOriginalContent);
	}

	@Override
	protected void onPause() {
		super.onPause();
		// The user is going somewhere, so make sure changes are saved

		String text = mText.getText().toString();
		int length = text.length();

		// If this activity is finished, and there is no text, then we
		// simply delete the note entry.
		// Note that we do this both for editing and inserting... it
		// would be reasonable to only do it when inserting.
		if (isFinishing() && (length == 0) && mCursor != null) {
			setResult(RESULT_CANCELED);
			deleteNote();
		} else
			saveNote();
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate menu from XML resource
		MenuInflater inflater = getMenuInflater();
		inflater.inflate(R.menu.editor_options_menu, menu);

		// Append to the
		// menu items for any other activities that can do stuff with it
		// as well. This does a query on the system for any activities that
		// implement the ALTERNATIVE_ACTION for our data, adding a menu item
		// for each one that is found.
		Intent intent = new Intent(null, getIntent().getData());
		intent.addCategory(Intent.CATEGORY_ALTERNATIVE);
		menu.addIntentOptions(Menu.CATEGORY_ALTERNATIVE, 0, 0,
				new ComponentName(this, NoteEditor.class), null, intent, 0, null);

		return super.onCreateOptionsMenu(menu);
	}

	@Override
	public boolean onPrepareOptionsMenu(Menu menu) {
		if (mState == STATE_EDIT) {
			menu.setGroupVisible(R.id.menu_group_edit, true);
			menu.setGroupVisible(R.id.menu_group_insert, false);

			// Check if note has changed and enable/disable the revert option
			String savedNote = mCursor.getString(COLUMN_INDEX_NOTE);
			String currentNote = mText.getText().toString();
			if (savedNote.equals(currentNote))
				menu.findItem(R.id.menu_revert).setEnabled(false);
			else
				menu.findItem(R.id.menu_revert).setEnabled(true);
		} else {
			menu.setGroupVisible(R.id.menu_group_edit, false);
			menu.setGroupVisible(R.id.menu_group_insert, true);
		}
		return super.onPrepareOptionsMenu(menu);
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
		// Handle all of the possible menu actions.
		switch (item.getItemId()) {
			case R.id.menu_save:
				saveNote();
				finish();
				break;
			case R.id.menu_delete:
				deleteNote();
				finish();
				break;
			case R.id.menu_revert:
			case R.id.menu_discard:
				cancelNote();
				break;
		}
		return super.onOptionsItemSelected(item);

	}

	private final void saveNote() {
		// Make sure their current
		// changes are safely saved away in the provider. We don't need
		// to do this if only editing.
		if (mCursor != null) {
			// Get out updates into the provider.
			ContentValues values = new ContentValues();

			// Bump the modification time to now.
			values.put(NoteColumns.MODIFIED_DATE, Long.valueOf(System.currentTimeMillis()));

			String text = mText.getText().toString();
			int length = text.length();
			// If we are creating a new note, then we want to also create
			// an initial title for it.
			if (mState == STATE_INSERT) {
				if (length == 0) {
					Toast.makeText(this, R.string.nothing_to_save, Toast.LENGTH_SHORT).show();
					return;
				}
				String title = text.substring(0, Math.min(30, length));
				if (length > 30) {
					int lastSpace = title.lastIndexOf(' ');
					if (lastSpace > 0)
						title = title.substring(0, lastSpace);
				}
				values.put(NoteColumns.TITLE, title);
			}

			// Write our text back into the provider.
			values.put(NoteColumns.NOTE, text);

			// Commit all of our changes to persistent storage. When the update completes
			// the content provider will notify the cursor of the change, which will
			// cause the UI to be updated.
			try {
				getContentResolver().update(mUri, values, null, null);
			} catch (NullPointerException e) {
				Log.e(TAG, e.getMessage());
			}

		}
	}

	/**
	 * Take care of canceling work on a note. Deletes the note if we had created it, otherwise reverts to the original
	 * text.
	 */
	private final void cancelNote() {
		if (mCursor != null)
			if (mState == STATE_EDIT) {
				// Put the original note text back into the database
				mCursor.close();
				mCursor = null;
				ContentValues values = new ContentValues();
				values.put(NoteColumns.NOTE, mOriginalContent);
				getContentResolver().update(mUri, values, null, null);
			} else if (mState == STATE_INSERT)
				// We inserted an empty note, make sure to delete it
				deleteNote();
		setResult(RESULT_CANCELED);
		finish();
	}

	/**
	 * Take care of deleting a note. Simply deletes the entry.
	 */
	private final void deleteNote() {
		if (mCursor != null) {
			mCursor.close();
			mCursor = null;
			getContentResolver().delete(mUri, null, null);
			mText.setText("");
		}
	}
}
